Only one Republican broke rank to vote with Democrats: Utah Sen. Mitt Romney, who voted to convict Trump on abuse of power. The vote on the second article, obstruction of Congress, came down on party lines.
The outcome was effectively assured after senators on Friday voted against hearing witnesses, also largely on party lines.
Read the latest news and analysis below:
A look back on Romney and Trump's complicated relationship
Romney’s announcement is also notable because of his complicated relationship with the president. In 2012, Trump endorsed Romney — who became the party’s nominee — and donated to his presidential campaign.
But as soon as Romney lost the election to President Barack Obama, Trump tweeted, "This was the Republicans election to win. @MittRomney is a good man but he just never connected with the people."
Several years later, when Trump ran for president in 2016, Romney spoke out against Trump in a speech and warned voters that the presidential candidate was "a phony, a fraud."
"His promises are as worthless as the degree from Trump University. He is playing the members of the American public for suckers. He gets a free ride to the White House, and all we get is a lousy hat," Romney said. "Donald Trump tells us that he is very, very smart. I'm afraid that when it comes to foreign policy, he is very, very not smart. If we Republicans choose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished."
In response, Trump lashed out against the former nominee during his campaign, saying, "Mitt is a failed candidate," Trump said. "He was begging for my endorsement. I could have said, ‘Mitt, drop to your knees,’ he would have dropped to his knees."
Once Trump won the 2016 election, however, the two appeared to make amends during a dinner in New York as Romney was rumored to be in the running for Trump’s secretary of state. That obviously didn’t work out, and Romney continued to criticize Trump before he came to the Senate, saying that there may be an "unraveling of our national fabric" if Trump didn’t apologize publicly for how he handled the 2017 white supremacist rally in Charlottesville.
More recently, Trump called Romney a "pompous ass" on Twitter last October after Romney blasted Trump for pressuring Ukraine to investigate the Bidens. And just a few weeks later, Romney admitted that he was behind an anonymous Twitter account with the name "Pierre Delecto" that liked critical tweets about Trump.
One source characterized the West Wing as "not f------ happy” on Wednesday, slamming Romney for looking to find the same spotlight he had in 2012, in their view. Still, one official noted that they’re not surprised, given Romney’s past statements and actions.
Hallie Jackson contributed reporting.
GOP chair — and Romney niece — reacts to his vote
Romney's decision may ease political pressure on 2 moderate Democrats
Romney's surprising announcement may ease the political pressure on two closely watched moderate Democrats, Sen. Joe Manchin of West Virginia and Sen. Kyrsten Sinema of Arizona, to vote to convict Trump. Both have carved out a reputation in their states as centrists who are willing to break with their parties, but Romney may provide them with bipartisan cover to vote to remove the president.
Speculation about Manchin and Sinema grew after two moderate Republicans, Sen. Susan Collins of Maine and Sen. Lisa Murkowski of Alaska, announced they would vote to acquit the president, raising the prospect that the GOP would be unified behind Trump in the verdict.
Dem senator gets emotional, thanks Romney after speech
During Romney's powerful speech on the Senate floor, the chamber was empty except for three Democrats listening intently: Sens. Chris Murphy of Connecticut, Patrick Leahy of Vermont and Brian Schatz of Hawaii.
Schatz wiped his eyes during Romney’s speech and, along with Leahy, followed Romney off the floor. Schatz told NBC News that he thanked Romney for his vote.
Schatz said he became emotional “because we all need to believe that this place can work, and this place can only work if individuals occasionally put country above party. And Mitt Romney just did that.”
He added, “I came to the floor because I was hoping. I didn’t talk to him about it, I just saw 2 o’clock and I cleared my schedule to come down.”
The only Republican in the chamber was Roger Wicker of Mississippi, who came in a few minutes late and stood by his desk just gazing at Romney. Sen. David Perdue, R-Ga., who was presiding over the Senate at the time, did not make eye contact with Romney once.
Schiff reacts: Romney displayed 'moral courage'
Full text: Romney's speech on why he'll vote to convict Trump of abuse of power
Sen. Mitt Romney, R-Utah, became the lone GOP senator to break with his party Wednesday, announcing in a speech on the Senate floor that he would vote to convict President Donald Trump of abuse of power — one of two articles of impeachment — in a vote expected later in the afternoon.
Kasie Hunt on why Romney's vote matters to Trump
Romney says he will vote to convict Trump for abuse of power
Sen. Mitt Romney, R-Utah, announced he will vote to convict President Donald Trump on abuse of power, one of the two articles of impeachment he faces.
Romney is the only Republican to announce a vote to convict the president.
Romney said Trump was "guilty of an appalling abuse of public trust" and that "what he did was not perfect."
He called Trump's conduct a "flagrant assault on electoral rights, electoral security, and fundamental values" and "the most abusive and destructive violation of one's oath of office that I can imagine."
As he started to read his speech, Romney appeared to choke up with emotion.
"The president's insistence that [Joe and Hunter Biden] be investigated by the Ukranians is hard to explain other than as a political pursuit," Romney said. "There's no question in my mind that were their names not 'Biden,' the president would never have done what he did."
Romney said he knew he was certain to face backlash from the president and his supporters and said it was the most difficult decision he's faced. He added that the vote allows him to tell his children and family that he performed his duty "to the best of my ability."
“With my vote I will tell my children and their children that I did my duty,” Romney said. “What the president did was wrong. Grievously wrong.”
Kaine defends Pelosi, calls Trump a 'jackass'
Sen. Tim Kaine did not mince words during an appearance on MSNBC's "Andrea Mitchell Reports" on Wednesday to talk about Trump's impeachment and the State of the Union address.
The Virginia Democrat said that Trump cannot claim exoneration because his impeachment trial was a "sham" and called the president a "jackass" for not shaking hands with House Speaker Nancy Pelosi after his address Tuesday night.
"He’s going to be acquitted," Kaine said. "I don’t think it’s an exoneration because the Senate trial was such a sham."
He added, "The refusal to allow evidence will put an asterisk by this. So, yes, it is an acquittal, but if I were the president, I would want exoneration and I don’t think exoneration is what you get when you engineer a sham rather than a trial."
He also excoriated Trump for ignoring Pelosi's outstretched hand and in turn defended the speaker for ripping her copy of the president's speech at the end of his address.
"I said, well, wait, so, he won't shake her hand and he gives a Medal of Freedom to somebody who's called her every name under the book for years," he said, referring to conservative radio host Rush Limbaugh, who has consistently trafficked in sexism and racism.
"And he stands up there and lies about health care, but we're going talk about how she should respond? I mean, he can behave like a jackass, but we have to jump all over her back? I mean, I don't get the double standard."
Maloney on Collins acquittal vote: 'It's transparently nonsense'
Jones: Re-election battle 'never crossed my mind' in impeachment decision
Jones spoke to reporters following his announcement that he would vote to convict Trump.
When asked if he was worried about his re-election, Jones said, "No. It has never crossed my mind. Did ya’ll hear that speech? Did anybody hear that speech? It has never crossed my mind."
He added that he "did what I thought was the right thing to do. It had been coming together."
NBC News noted that Jeff Sessions, who once held Jones' seat and is now running to reclaim it, is already attacking Jones over his impeachment vote
"So?," he said.